Pagham Coastal Protection

 

We have tried here to provide as much current information as possible about the situation at Pagham Beach and the surrounding area. If you cannot find the answer to your question, please email coast.protection@arun.gov.uk

 

Background

The beach at Pagham is comprised of a dynamic shingle frontage with sandy clay lower foreshore, the nature of which is unpredictable. Adjacent to the south west of the site is the designated site of Pagham Harbour, which has an influence on the natural development of the frontage. The upper foreshore is characterised by vegetated shingle and is designated SSSI.  In addition, there are other environmental designations e.g. SPA, Ramsar and a Nature Reserve.

The history of flooding and erosion at Pagham Beach stretches back for several decades. Most notably, as of 2009, an increasing proportion of the frontage became subjected to erosion and scouring as the Harbour realigned through the growth of Church Norton shingle spit. The alignment forced the Harbour channel back towards the beach eroding tens of thousands of cubic metres of shingle.

The storm events that took place during 2013, ‘14 and ‘15 triggered losses of beach volume at West Front Road, placing properties at an increased level of coastal erosion risk.  The spit continued to grow and the focus of erosion moved. There were occasional periods when the crest width between the properties and face of the beach was reduced in places to less than 10m and Arun District Council carried out several emergency schemes, in rapid response to the situation, (see below for revetment and shingle recycling) to bolster the beach and reduce the likelihood of loss through coastal erosion. Of those properties, the 15 which were most at risk (to the west) are now protected by a rock revetment (see below). The beach in front of a few properties immediately east of the most westerly groyne (Groyne 4) had been scoured following the growth of the spit and the partial collapse of that groyne.

Subsequently, in the winter of 2015/16, the shingle spit was subjected to persistent overtopping.  A full breach of the spit followed shortly afterwards (April 2016), with the dominant channel migrating in a south westerly direction. The events allowed the eastern end of the severed spit to weld onto the mainland, easing the scour current that had been persistently eroding the beach. The welded material now offers an increased standard of protection for properties on West Front Road.

In the years that followed (’16-present) the beach in front of East Front Road has been subjected to erosion.  Crest widths have at times been reduced locally to less than 10m and ADC has carried out emergency shingle recycling schemes in order to protect properties there. 

The dynamic nature of the system means that there is no certainty in how the system will develop and therefore prediction on future developments is deemed inappropriate.  However, some very broad assessments have been made and the following conclusions have been drawn;  The developments  may either close the Harbour, potentially effecting the adjoining surface water drainage network, or open more fully, exposing the inner harbour to increased wave action, or,  the Church Norton spit and associated delta and shingle bars may redevelop with similar or different effects to that which we have seen previously.

 

Management of the Pagham Coastline

The coast around England is typically managed by either the Environment Agency (EA) or the Local Authority. At Pagham, Arun District Council manages the open coastline in front of the properties, whilst the EA maintains the defences inside and fronting the harbour. 

The EA has two main roles at Pagham. One is as the Coastal Overview body. This role requires the Environment Agency to assess projects for their viability and to distribute the funding put aside by Central Government for flooding and erosion projects. Another role is as a "permissive" maintainer of the inner harbour bunds. Under this role, a project was completed to improve the defences along the eastern part of the harbour to reduce flood risk to 88 properties at Pagham.

Neither Arun District Council nor the Environment Agency has a duty to protect the coast from erosion or flooding. The various Acts of Parliament under which Arun DC works, provides powers to reduce the risk of erosion and similarly the Environment Agency to reduce the risk of flooding.

Natural England is the Government's statutory adviser on the natural environment. Advice is available to regulators such as Arun DC and the EA on issues related to wildlife and designated nature conservation sites. Natural England does not make decisions on coast protection or flood defence issues and is not responsible for undertaking coastal defence works. Natural England’s advice is sought when environmental interests might be affected, and this advice is taken into account when decisions are made.

Pagham beach is a dynamic area and its management has become increasingly difficult as socio-economic and environmental factors have become more influential. Managing such a dynamic coastline with a multitude of conflicting interests is both resource intensive and challenging for Arun District Council.

Arun District Council has followed the ‘Hold the Line’ SMP policy in recent years. Due to the dynamic nature of this stretch of coastline, the Coastal Defence Strategy for Pagham beach has recommended an ‘Adaptive Management’ approach. However, it must be understood that funding of this option can only continue if future schemes remain economically viable and provide a positive cost:benefit to the taxpayer.

 

Actions Taken so Far at Pagham

Historically, shingle was recycled from the near-shore shingle banks and placed along the Church Norton frontage, to help strengthen the southern spit. In 2003, the spit on the Church Norton side of the harbour started to accrete (grow) naturally. There was therefore no need to continue bolstering the spit and these activities were stopped. It is important to note that Pagham Harbour was not dredged.

A revetment was installed in 2013 in order to protect the properties at highest risk of erosion (at the time) at West Front Road.  At the time of construction there was an increase in scour to the area and Arun District Council, along with the Environment Agency, believe that the revetment was key to the Pagham residents’ protection during the successive storms of winter 2013-2014. Had the revetment not been in place, we would have lost many more metres of beach crest and probably several properties too.

The storms of 2013-2014 are thought to have contributed to the accelerated the growth of the Church Norton spit which, in turn, changed the patterns of the currents in the harbour mouth. The toe of the revetment settled and the District Council undertook initial works to stabilise it.  Over the course of 2014 and 2015 six schemes of shingle recycling were undertaken in order to provide a higher level of protection to relevant areas of West Front Road. In addition, rock was delivered and/or redistributed and shingle geobags were positioned to further shore up two nearby groynes and the revetment. 

Prior to the natural breach of the Church Norton spit in 2016, there were many members of the community who believed that Arun DC should endeavour to ‘cut the spit’, to realign the harbour mouth and reduce the erosion at West Front Road.  Arun DC was unable to progress this option due to the time and cost associated with developing and delivering the option which sought to realign the harbour to its position prior to 2003 (estimated at £1.5million over 5 years – and more over the full lifetime of such a scheme).  In addition, there was some uncertainty that it would solve the problem in the longer term, plus concerns about the technical challenges associated with such a proposal and the potential increase of the flood risk within the harbour.

There was the concern that cutting a new channel through the spit was also likely to have effects on the Harbour and its habitats which would require careful assessments. Pagham Harbour is of National and International environmental importance and this would have needed to be considered through a proper assessment and therefore would need to be factored into the project cost and timeframe.  The current Central Government framework of approvals and funding has therefore led us to follow the Adaptive Management recommendation as set out in the Pagham to East Head Coastal Defence Strategy.

Pagham Parish Council submitted a planning application to ‘cut the spit’ in December 2015.  Following an 18 months process, planning permission was granted for the works in June 2017. However, following the 2016 breach and subsequent developments, the current volumes and beach configurations are such that the scheme is not viable.  The project is now being administered by Pagham Flood Defence Community Interest Company (PFDCIC). 

Whilst blocking the harbour mouth is technically more feasible and potentially cheaper than cutting the spit, actively closing Pagham Harbour presents several technical and environmental challenges. The Harbour would cease to be tidal, this presents a number of issues, including water quality and it would mean that water would permanently cover most of the mudflats and saltmarsh. The current natural environment would entirely change, creating a new habitat as the saline conditions changed to brackish and then freshwater over time. There is also a risk that the spit may breach making it likely to reopen and therefore require further funded actions. It is therefore the belief that actively closing the harbour is not the right solution.

Following the breach of the Church Norton spit in 2016, the shingle mass migrated shoreward and eventually welded to the foreshore.  Over the transition period, erosion and scour followed its path east.  As such, our focus of remedial works realigned to the frontage at East Front Road in front of the Yacht Club.  Over the past four years (up to Spring 2020) multiple shingle recycling schemes (of varying scale) have been completed, focussed on this area.

 

The Revetment

Arun District Council chose to use a rock revetment because at the time of appraisal it was identified as the ‘preferred option’ in accordance with the national Flood and Coastal Erosion Risk Management Grant in Aid guidance. The option met the criteria set out by the project board meeting objectives such as; being cost effective, having a short implementation time and would have minimal environmental impacts. A further benefit is that the structure could be dismantled and redeployed elsewhere if conditions at Pagham change to the point where a revetment was no longer needed. Although the revetment was not specifically designed to combat the scour current that came after the erosion of the foreshore, the structure has proven effective during the severe weather of 2013 and 2014 winters. The cost of the initial construction of the revetment was in the order of £500,000. Arun DC had to carry out some additional works including stabilisation of some of the rock and recycling shingle. The revetment is currently providing a 20 metre wide beach in front of the properties, which is typically sufficient to absorb wave energy and reduce overtopping to a 1 in 200 year standard of protection (0.5% chance of flooding in any year).

 

Risks

There can be no guarantee that homes are 100% safe. Living close to the sea always carries some level of risk; homeowners should be aware of this and should take appropriate precautionary measures if they consider it necessary. Across the whole coastal frontage at Pagham, there are 102 properties which could be at risk of flooding and/or erosion.

Natural processes, including littoral drift, have carried material from the southwest along the beach to form the spit. The rate of development of the spit and associated ebb delta has been quite remarkable and it is the natural development that forms part of its designation. It must be remembered that the land upon which Pagham Beach Estate now resides is a shingle spit which grew up after 1875. It should also be noted that just as the rate of material coming along the beach from the west has increased, it could also reduce.

We are aware many people within the village are concerned about becoming at risk if the front line of properties were to erode into the sea. The land within Pagham Village is higher relative to Pagham Beach and slopes upwards from behind Pagham Beach (after an initial dip). There is no flood route from the coast, which would put additional properties at risk. The risk remains from the harbour overtopping the existing defences, placing 88 properties in the extreme south-west corner of the village, and the Church Farm caravan park at significant risk of flooding. However, the Environment Agency led on a partnership scheme to improve the defences on the eastern side of Pagham Harbour which has seen this risk significantly reduced.

Pagham is a costal location and is exposed to tidal flood and coastal erosion risks. We can reduce these risks significantly though defensive actions but cannot remove them completely. As noted above, a risk remains from the harbour overtopping the existing defences and flooding up to 88 properties and Church Farm Caravan Park. However, there is an emergency plan for Pagham, this includes preparations by Arun District Council and the emergency services in case a breach does occur.

All of the beaches around our coasts are monitored, but following the adoption of the Pagham to East Head Coastal Defence Strategy in 2010, a further study as recommended in the Strategy, was undertaken. This presented a number of ‘triggers’ which set out courses of action for various beach crest widths: 20 metres is a warning width when Arun DC would start monitoring the beach more frequently and begin discussing with the EA and Natural England ways forward. At 15 metres, ADC would take action, designing, seeking approval for, and putting in place, a flood/erosion risk management project. If the beach crest reduced to 10 metres, ADC would begin emergency works to rebuild the beach width.

 

Actions Being Taken

Arun District Council continues to monitor the situation at Pagham Beach on a weekly basis.  We carry out visual inspections, assess and photograph any changes.  In addition, the Regional Monitoring Team carry out bi-annual surveys. The results of which are free and freely available from the Channel Coast Observatory.  

The key stakeholders have been working closely with the Pagham Coastal Issues Advisory Group to establish short to medium term plans for the coastline. 

If you would like to know more, please email coast.protection@arun.gov.uk